Effect of excess antimony on TE-properties of cobalt-antimony based skutterudite materials prepared by gas atomizing and sintering process

In order to construct the mass production process of thermoelectric materials that accomplish wide range supply for various industrial fields, in previous study, gas atomizing and sintering process was investigated for cobalt-antimony based Skutterudite materials. It was found that the combination process of gas atomizing and sintering process is useful for mass production of high quality thermoelectric materials. Because those process is simple without mixing or grinding process and any kind of materials can be made as far as they can be melted in a same crucible in a same time. The mean diameter of gas atomized powder is less than 100 m, and also the inner structure of them is fine including every necessary element. Accordingly gas atomized powder can be sintered in a short time by both methods of spark plasma sintering and hot press sintering. Thermoelectric properties of materials that were made in this process were compared with the same kind of material which was made in laboratory scale. Substituted type materials attained almost aimed value of ZT, however filled type material could not get the same ZT value which was made in laboratory scale. One of the main reasons of low ZT value of p-type was considered to be concerned with excess antimony owing to large-scale production. Another reason was considered to be oxide effect that was introduced in the process of gas atomizing. These factors seem to be also important for n-type materials to get higher properties.